The International Lake Ontario-St. Lawrence River Board will temporarily reduce outflows from Lake Ontario to increase water levels on Lake St. Lawrence the second weekend of October. This effort will provide marinas and shoreline dock owners an opportunity at the end of the season to remove recreational boats more easily. The board will temporarily reduce outflows through the Moses-Saunders Dam for a 72-hour period from noon on Friday, October 8, through noon on Monday, October 11, to raise water levels on Lake St. Lawrence. Based on the current forecast, Lake Ontario outflows are expected to be temporarily reduced by approximately 8,800 c.f.s. to reach a target water level of about 239.83 feet on Lake St. Lawrence at Long Sault Dam during the holiday weekend in October.
“Decreasing the outflow through the dam will cause water levels immediately upstream on Lake St. Lawrence to rise. However, there will be a temporary decline in water levels downstream of approximately 3.9 to 5.9 inches at Lake St. Louis and Montreal,” said Steve Durrett, United States Co-Chair of the International Lake Ontario-St. Lawrence River Board.
The board will continue to monitor weather forecasts and water supply conditions to refine this strategy as necessary in the coming weeks. The board has been operating under regulation plan flow since July 17. The discretionary flow reduction is permitted by Plan 2014 and considered a minor deviation.
Water levels on Lake Ontario are expected to increase by less than a third of a centimeter. As required by the IJC’s Directive, the small amount of water that will be stored on Lake Ontario during this temporary flow decrease will be completely offset by an increase in flow later in October.
The 1.6 inches of water stored on Lake Ontario during the major deviations (undertaken from May 28 through July 16, 2021) will be retained through mid-October to provide a small benefit to recreational boaters in the Thousand Islands and upper St. Lawrence River.
Information on hydrologic conditions, water levels, and outflows, including graphics and photos, are available https://www.ijc.org/en/loslrb on the Board’s Facebook page.
Provided information
